Best known for his Constable series of books based on his own experiences as a village policeman in the 1960s and which inspired the hugely popular TV series Heartbeat, Nicholas Rhea is a prolific writer. Since leaving the police force thirty years ago, by which time he had reached the rank of inspector, Rhea has penned a string of successful crime novels and his latest book, Confession at Maddleskirk Abbey, is out in hardback now.

Set in a fictional Yorkshire abbey with its own private police force of monk-constables (or “monkstables” as Rhea refers to them), the book’s plot centres on a woman’s confession of murder made to one of the monks, Father Will Redman. The sanctity of the confessional means that Redman can’t discuss the woman’s crime or even report it to the police – and when a body is discovered in nearby woodland his moral dilemma grows.

As one of the monk-constables Redman wants to help Detective Chief Superintendent Napier and his team who are investigating the murder, but he is compelled to remain silent. As the hunt for the killer intensifies some disturbing facts begin to emerge about the violent past of one of the Abbey’s older monks, who has mysteriously disappeared.

Rhea says he knew he wanted to write about part-time police officers and came up with the idea of the “monkstables” for his 2013 book Murder at Maddleskirk Abbey, loosely based on the private police force at York Minster. “I live in Ampleforth where we have an abbey on the doorstep and I know it quite well,” he says. “I go to the church there sometimes, but the book is not about that abbey, it is entirely fictitious.”

The Maddleskirk books also feature brief appearances by Rhea’s most famous character Constable Nick of Aidensfield (and Heartbeat), now retired, who helped to set up the Abbey’s special police force.

Not surprisingly the passages in the book which deal with the specifics of police procedure feel very authentic but Rhea is aware that he has to be mindful of not getting too bogged down in minutiae. “You have to be careful because you can get a bit boring on those details,” he says. “I taught criminal law and police procedure for many years and when I left the force I was steeped in it, but that was many years ago now and the law changes all the time. You need to work hard to keep up with it and I haven’t got time to do that because I am concentrating on my writing.” Rhea is certainly diligent and focussed in his approach to his writing, when we speak he tells me he has three books on the go at the moment – a crime thriller set in Northumberland, a non-fiction book about the folklore of the North York Moors and another novel that revisits the Constable series but is set ten years prior to the original books.

“I write every day, 9 til 5, five days a week and take Saturday and Sunday off,” he says. “I am very disciplined and strict about my routine. I’m never short on ideas and the main thing is to get them down on paper. No matter how daft they may sound, when they are down on paper then you can do something with them.”

But it is Heartbeat with which Rhea will always be most associated – after our chat he has an interview lined up with a news reporter from Calendar about Goathland’s village shop Aidensfield Stores, which had a starring role in the series, being up for sale; and there is a stage play in the offing on which he will be an advisor.

“Heartbeat did capture people’s imagination,” he says. “There is a nostalgia for the 1960s, which was a period of great change, and italso showed a softer image of the police which was quite true – we were there to help.”

• Confession at Maddleskirk Abbey by Nicholas Rhea, published by Robert Hale Limited, £19.99.